Each of the triangular numbers that are below 1000 is written on a separate card. Some of these cards are then placed in a circle so that, viewed from the center, the righthand digit of each card matches the lefthand digit of the card to its right. No tricks are used such as turning a card upsidedown.
What's the maximum number of digits that can appear on such a subset of the cards?
15, 55, 528, 861, 171, 105, 595, 561, 153, 351
Much of what I said in "One Ring" (first comment here) is pertinent.
I've "upped" my ante to 10 numbers with a total of 28 digits.
Note: While some numbers end in "0" I dismissed them since we couldn't realistically have leading "0's", could we? Also single digit numbers were ruled out because righthand/lefthand digits implies at least two digits.
Edited on January 10, 2008, 8:10 am

Posted by brianjn
on 20080110 07:44:10 